The proportion of children, adolescents, and adults who are overweight or obese is increasing. The number of overweight people has doubled in the last two to three decades, and such increases are found in all age, race, and gender groups.
Cellulite is a common skin condition related to the accumulation of excess subcutaneous fat (adipose tissue) within fibrous septae. Irregularities in the structure of the fibrous septae can create the appearance of cellulite, which is typically seen as an unsightly irregular, dimpled skin surface. Cellulite is often found in abundance in overweight and obese individuals, e.g., on the thighs, hips, and buttocks.
There is a demand for apparatus and procedures that will reduce the overall volume of adipose tissue and/or reshape subcutaneous fat. There is also a demand for treatments that will decrease the appearance of cellulite for cosmetic purposes.
Prior art interventions for decreasing or reshaping adipose tissue include liposuction and lipoplasty, massage, low level laser therapy, and external topical compositions, such as “cosmeceuticals,” or a combination of such treatments. Liposuction and lipoplasty are invasive surgical techniques in which subcutaneous fat is excised and/or suctioned from the body. These procedures may be supplemented by the application to the targeted adipose tissue of various forms of energy to emulsify the fat prior to its removal, e.g., by suction.
Although liposuction and lipoplasty can effectively remove subcutaneous fat, the invasive nature of these procedures presents the inherent disadvantages of surgery, including high cost and extended recovery times, as well as the associated risks such as infection, excessive bleeding, and trauma.
Non-invasive interventions for subcutaneous fat reduction, or diminution of the appearance of cellulite, including massage and low-level laser therapy, are significantly less effective than surgical intervention.
Some cosmetic skin treatments effect dermal heating by applying radiofrequency (RF) energy to the skin using surface electrodes. The local heating is intended to tighten the skin by producing thermal injury that changes the ultrastructure of collagen in the dermis, and/or results in a biological response that changes the dermal mechanical properties. The literature has reported some atrophy of sub-dermal fat layers as a complication to skin tightening procedures.
During electrosurgical procedures that target subcutaneous fat, the depth of muscle tissue below the surface of the skin may greatly influence the distribution of electric currents, and therefore the heating distribution within the tissues. Prior art apparatus and methods have not adequately addressed electric current distribution in subcutaneous tissue in relation to variations in the thickness or depth of skeletal muscle tissue underlying a targeted tissue comprising subcutaneous fat.
US Patent Application Publication No. 2006/0036300 (Kreindel) discloses lipolysis apparatus having one or more protruding, terminal electrodes. In methods of Kreindel, a region of tissue may be deformed, and the electrodes may contact both deformed and non-deformed skin.
U.S. Pat. No. 6,488,678 to Sherman discloses apparatus including a catheter having an array of electrodes at the catheter distal end, and adapted to position the electrodes at a biological site. A backplate is positioned proximal to the biological site, such that the biological site is interposed between the backplate and the electrodes. Power provided to the electrodes has a duty cycle with on and off periods. During a first segment of the on period, energy flows between the backplate and an electrode, while during a second segment of the on period, energy flows between the electrodes. The flow of energy can be controlled by adjusting the phase angle of the power.
U.S. Pat. No. 6,635,056 to Kadhiresan et al. discloses a system including a catheter for use in ablation therapy, e.g., of cardiac tissue, in which the system uses controllable differences in amplitude of power signals to establish repetitive bipolar current flow between sets of electrodes, and a backplate to establish unipolar current flow.
U.S. Pat. No. 7,151,964 to Desai discloses a multi-electrode catheter for ablation of endocardiac tissues. The electrodes are adapted for being collapsed for introducing the catheter into the patient's body, and for being fanned out into an array during ablation of tissue, such as endomyocardium. In a preferred embodiment of the '964 patent, a two-phase RF power source is used with an orthogonal electrode catheter array comprising one central electrode and four peripheral electrodes. The central electrode is connected to ground voltage of the power supply; and the peripheral electrodes form two diagonal pairs connected to two individually phased voltages.
U.S. Patent Application Publication No. 2007/0203482 (Ein Gal) discloses a system including at least two target electrodes, at least one return electrode, and at least two RF power sources in electrical communication with the electrodes. Each target electrode defines a separate monopolar energy delivery channel, the at least one return electrode being common to both channels. The target electrodes are operable in a bipolar mode. A waveform manipulator controls and manipulates RF energy waveforms to the target electrodes to selectively provide pure monopolar, pure bipolar and a blend of monopolar and bipolar modes of energy delivery for RF tissue ablation.
It can be seen that there is a need for an effective modality by which subcutaneous fat tissue may be non-invasively reshaped, and/or sculpted for the cosmetic improvement of human skin and/or body shape. There is a further need for a non-invasive procedure for effectively and efficiently decreasing the volume of subcutaneous adipose tissue in a person who may be obese or overweight.